Last Friday’s Gallup daily tracking poll showed that 51 percent of Americans approved of President Obama, and 42 percent disapproved. Starting last weekend, he launched a full-scale media blitz, which included interviews with five Sunday talk shows and an appearance on David Letterman’s show. So how has all of this exposure worked out for him? Not too well, as it turns out. Today’s Gallup has Obama at a 50 percent approval rating, with 42 percent disapproving. That actually is tied for the lowest Gallup approval rating of his presidency.